When an instance of the ttymon port monitor is invoked by the SAC, ttymon starts to monitor its ports. For each port, the ttymon port monitor first initializes the line disciplines, if they are specified, and the speed and terminal settings. The values used for initialization are taken from the appropriate entry in the /etc/ttydefs file.
The ttymon port monitor then writes the prompt and waits for user input. If the user indicates that the speed is inappropriate by pressing the Break key, the ttymon port monitor tries the next speed and writes the prompt again.
If autobaud is enabled for a port, the ttymon port monitor tries to determine the baud rate on the port automatically. Users must press Return before the ttymon port monitor can recognize the baud rate and print the prompt.
When valid input is received, the ttymon port monitor does the following tasks:
Interprets the per-service configuration file for the port
Creates an /etc/utmpx entry, if required
Establishes the service environment
Invokes the service associated with the port